VNW Transistor Dummy Elements for Dimensional Variation
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Solution Overview
Problem
In semiconductor device manufacturing, variations in dimensions and impurity profiles of Vertical Nano Wire (VNW) elements at the periphery of a group can lead to inconsistent characteristics, such as resistance values, due to manufacturing variations, affecting the performance and reliability of VNW elements like transistors, diodes, and resistors.
Innovation Solution
The semiconductor device incorporates dummy VNW elements arranged around functional VNW elements, which are electrically isolated to prevent them from functioning as transistors, diodes, or resistors, thereby minimizing manufacturing-induced variations by providing a reference for maintaining consistent characteristics in the functional elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VNW elements are arranged in a group to increase device density, then productivity and area utilization are improved, but manufacturing variations cause peripheral elements to have different dimensions and impurity profiles leading to characteristic variations
Solution Approach 1:
The patent creates dummy VNW elements that are identical copies of functional VNW elements in terms of structure and material composition. These dummy elements are positioned at peripheral locations to replicate the manufacturing conditions experienced by functional elements, thereby capturing and compensating for edge effects and manufacturing variations without consuming additional functional device area.
Solution Approach 2:
The dummy VNW elements act as intermediary structures between the manufacturing process and the functional VNW elements. By positioning dummy elements at peripheral locations, they serve as mediators that absorb manufacturing variations and provide reference data for adjusting the fabrication process, thereby protecting the functional elements from direct exposure to these variations.
2Manufacturing precision
If dummy VNW elements are added to compensate for manufacturing variations, then manufacturing precision and characteristic consistency are improved, but device complexity and area occupation increase
Solution Approach 1:
The dummy VNW elements are designed to be homogeneous with the functional VNW elements in terms of structure, material composition, and fabrication process. This homogeneity allows the dummy elements to accurately reflect manufacturing variations while maintaining the same fabrication workflow, thereby improving characteristic consistency without introducing additional process complexity or requiring different materials.
3Area of stationary object
If peripheral VNW elements are used as functional elements to maximize area utilization, then area efficiency is improved, but their characteristics vary due to manufacturing variations affecting dimensions and impurity profiles
Solution Approach 1:
The patent implements preliminary action by placing dummy VNW elements at peripheral locations before the actual functional device operation. These dummy elements undergo the same manufacturing process as the functional elements and provide advance information about manufacturing variations. This preliminary data is then used to adjust and optimize the fabrication process for the functional elements, ensuring uniform characteristics before they are deployed.
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate; a VNW transistor being a functional element provided with a first projection formed on the semiconductor substrate, having a semiconductor material, and having a lower end and an upper end; a dummy functional element provided with a second projection formed on the semiconductor substrate, having a semiconductor material, having a lower end and an upper end, and arranged side by side with the first projection; and a first wiring formed above the first projection and above the second projection, electrically connected to the upper end of the first projection, and electrically isolated from the upper end of the second projection. Consequently, the semiconductor device capable of suppressing variation in characteristics of the VNW transistors is realized.